I am sure MathML took off somewhere, but I never really saw it. MathJax seems to have a chance at being a practical solution that offers a high quality display of LaTeX and MathML math notation in HTML pages.

MathJax grew out of the popular jsMath project, an earlier Ajax-based math rendering system developed by Davide Cervone in 2004. In the intervening time, there have been many significant developments relevant for web publication of mathematics: consolidation of browser support for CSS 2.1, Web Font technology, adoption of math accessibility standards, and increasing usage of XML workflows for scientific publication. Consequently, Cervone and others are designing and developing MathJax from the ground up as a “next-generation” platform, while still benefiting from the extensive real-world experience gained from jsMath.

Wow, at first I assumed this was like that silly jQuery plugin that called out to a web service to do the rendering, but MathJax actually uses JavaScript to generate properly formatted text. Impressive.